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WO1990010786A1 - Regleur automatique de longueur - Google Patents

Regleur automatique de longueur Download PDF

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Publication number
WO1990010786A1
WO1990010786A1 PCT/GB1990/000293 GB9000293W WO9010786A1 WO 1990010786 A1 WO1990010786 A1 WO 1990010786A1 GB 9000293 W GB9000293 W GB 9000293W WO 9010786 A1 WO9010786 A1 WO 9010786A1
Authority
WO
WIPO (PCT)
Prior art keywords
housing
adjuster
screw member
spring
guide element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB1990/000293
Other languages
English (en)
Inventor
Stewart Clark Mcrobert
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GKN Technology Ltd
Original Assignee
GKN Technology Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by GKN Technology Ltd filed Critical GKN Technology Ltd
Publication of WO1990010786A1 publication Critical patent/WO1990010786A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/20—Adjusting or compensating clearance
    • F01L1/22—Adjusting or compensating clearance automatically, e.g. mechanically

Definitions

  • This invention relates to a mechanical automatic length adjuster comprising an internally screw-threaded housing, an externally threaded screw extending within the housing and spring means acting.axially on the screw to cause it to rotate and advance outwardly of an open end of the housing to lengthen the adjuster; the co-operating thread forms of the screw and the housing being so configured that the screw will rotate freely and advance out of the housing on co-operating running flanks of the threads under the axial spring bias.
  • a length adjuster comprising a self-contained device preferably for use as an automatic clearance adjuster in a valve train mechanism of an internal combustion engine or, alternatively, for use as a self- levelling device or as a belt tensioner.
  • a length adjuster is described in GB-A-2033472 wherein the housing is incorporated as an integral part of a rocker arm, or the screw is incorporated as an integral part of a valve stem, for automatic clearance adjustment in a valve train mechanism of an internal combustion engine.
  • the spring means comprises a coil compression spring acting between the screw and a fixed abutment at one end of the housing; the screw being formed with a central bore for receiving the spring. It has been proposed to manufacture such a length adjuster by tapping a thread into the housing and by rolling or cutting a corresponding thread on the screw. However, it has been found that a screw with such a central bore can suffer distortion during the thread forming process and/or during subsequent heat treatment.
  • a mechanical automatic length adjuster comprising an internally threaded housing, a screw member within said housing having an external thread form configured to run within the thread form of the housing, the thread forms exhibiting a relatively high friction in one direction of axial loading of the screw threads compared with a relatively low friction in the opposite direction of axial loading, spring means acting on the screw member to bias .it in the said opposite direction of axial loading and thus to urge the screw member in a direction to advance axially of the housing with the thread form being configured to provide co-operating running flanks and locking flanks whereby the screw member will rotate and advance axially of the housing when the axial thrust of the spring means urges said running flanks together characterised in that the screw member is of solid form and the spring means comprises a coil compression spring within the housing acting upon abutment means to bias the screw member in a direction outwardly of an open end of the housing.
  • solid form as used in the preceding paragraph and throughout this specification and claims in relation to the screw member is to mean that the screw member is not provided with any substantial internal reliefs although it may be provided with a small diameter axial bore or bores for the supply of lubricant.
  • the inner end of the screw member is preferably provided with a central axially extending spigot of lesser diameter than the outside diameter of the screw member providing said abutment means as an axially facing annular shoulder extending from the spigot to the outside of the screw member and, conveniently, said spigot comprises an integral solid cylindrical extension of the screw member.
  • a guide element is located within the housing extending axially within the spring from a closure element at that end of the housing remote from the open end thereof, the spring bearing upon a further abutment means on said guide element.
  • Said guide element is conveniently of cylindrical configuration wherein said further abutment means comprises an annular shoulder facing axially towards the said abutment means on the screw member.
  • closure element and the adjacent end of the guide element are configured to permit a low friction bearing rotation of the guide element upon the closure element and, in one embodiment, said closure element may comprise a domed spring element located within the end of the housing and the end of the guide element may be provided with a concave depression of a greater radius of curvature than the radius of curvature of the domed spring element upon which the guide element bears.
  • a ball-bearing is located between socket means provided in opposed relation respectively on said closure element and on the end of the guide element.
  • the automatic mechanical length adjuster of the invention may be constructed and arranged as a self-contained mechanism for use as an automatic clearance adjuster in a valve train mechanism of an internal combustion engine or may be provided for use as a belt tensioner, a brake adjuster or as a self-levelling device or for use in any other application where such an adjuster can conveniently be incorporated.
  • the housing of the adjuster may comprise an integral part of a rocker arm.
  • Figure 1 is a side part-elevation, part cross- sectional view of an automatic mechanical length adjuster constructed in accordance with the invention.
  • Figure 2 is a similar view of an alternative form of such an adjuster.
  • FIG. 1 of the drawings there is shown a self-contained mechanical automatic length adjuster which, for example, may be utilised as an automatic clearance adjuster in the valve train mechanism of an internal combustion engine in a similar manner to that described in GB-A-2160945, the disclosure of which is hereby incorporated by reference. It should, however, be appreciated that the adjuster may be advantageously utilised in other applications such as, for example, as a belt tensioner, a brake adjuster or as a self-levelling device or in any other convenient application.
  • the adjuster illustrated in Figure 1 comprises a steel or cast iron housing 10 of generally cylindrical configuration with a central axial through bore 12 which is tapped to provide an internal screw-thread of buttress thread form.
  • a solid steel screw 14, also of generally cylindrical form, has an external screw-thread rolled or cut thereon of a buttress thread form complementary to the internal buttress thread form of the housing 10.
  • Such co-operating buttress thread forms provide co-operating running flanks and locking flanks thereon and are conveniently formed to the same geometrical criteria as described in GB-A-2160945, the disclosure of which is hereby incorporated by reference.
  • the screw 14 extends within the housing 10 and is provided at its inner end with an integral central cylindrical spigot 16 of an external diameter which is less than the outside diameter of the screw 14. Between the spigot and the outside of the screw there is thus provided an annular shoulder 18 having a face directed axially inwardly of the housing and providing abutment means for a coil compression spring 20 located within the housing and acting upon the screw to bias it in a direction outwardly of the open end of the housing.
  • a guide element 22 in the form of a .solid steel member of generally cylindrical configuration having an outside diameter slightly less than the internal diameter of the coil spring 20 and extending axially within the spring. That end of the guide element 22 remote from the screw 14 is provided with an enlarged cylindrical head 24 providing an annular shoulder 26 having a face axially directed towards the corresponding annular shoulder 18 on the screw and providing a further abutment means for the other end of the coil compression spring 22.
  • a closure element for said end of the housing comprises a spring steel domed element 30 press fitted into the counterbore to abut against the shoulder 28.
  • the adjacent end face 32 of the head 24 of the guide element is provided with a concave depression of a radius of curvature which is greater than the radius of curvature of the domed closure element whereby the guide element head 24 bears upon the closure element 30 under the action of the coil compression spring 20 in a low friction freely rotatable manner and with a self- centering action with respect thereto.
  • the screw 14 is provided with a domed head 34 although the specific configuration of this outer end of the screw is not relevant to the present invention.
  • the screw 14 under the action of the coil compression spring 20, the screw 14 is urged axially outwardly of the housing 10 and will rotate freely and advance out of the housing on the co-operating running flanks of the buttress thread forms solely under the axial spring bias of the compression spring.
  • the screw Conversely, the screw will be prevented from rotation by co-operation between the locking flanks of the buttress thread forms upon application of axial forces to the screw in a direction against the direction of the spring bias.
  • the provision of the screw 14 as a solid steel member enables the buttress thread form to be readily rolled or cut thereon without any possibility of distortion during the thread forming operation and/or during the subsequent heat treatment operation.
  • the manufacture of the housing 10 is facilitated by the through tapping of the internal threads followed by the relatively simple operation of the formation of a counterbore to receive the closure element 30 in the form of a press fitted spring steel member.
  • the co-operation between the convex domed surface of the spring steel element 30 and the concave depression in the adjacent end face 32 of the guide element enables the guide element to bear freely for rotation with extremely low friction upon the spring steel closure element and with a self-centering action.
  • the adjacent end of the head 24 of the guide element 22 is also provided with a hemispherical socket 44 to receive the ball-bearing between it and the corresponding opposed socket ' 40 on the closure element 38 thereby providing for the guide element 22 to bear in a low friction freely rotatable manner upon the closure element 38 and to be centred relative thereto.
  • the automatic length adjustment features of the mechanism function in a manner similar to that described with reference to the embodiment shown in Figure 1 of the drawings.
  • the embodiment of automatic mechanical length adjuster shown in Figure 2 may be utilised as an automatic clearance adjuster in a valve train mechanism of an internal combustion engine or, alternatively, as a belt tensioner, a brake adjuster or as a self-levelling device or for use in any other convenient application.
  • the screw member 14 is of solid form in accordance with the invention; that is to say, it is not provided with any substantial internal reliefs although, as illustrated, it is provided in each of the two embodiments with a small diameter central axially extending through bore for the supply of lubricant.
  • the automatic mechanical length adjuster of the invention may be provided as an integral part of a rocker arm for use as an automatic clearance adjuster in a valve train mechanism of an internal combustion engine.
  • the housing is provided as an integral part of the rocker arm and the other constituent parts of the adjuster, i.e. the screw, the coil compression spring, the guide element and the closure element may be constructed as described above with reference to the embodiments illustrated in Figures 1 and 2.
  • the housing 10, the screw 14 and the guide element 22 are formed of metal but it is envisaged that all of these parts of the adjuster may alternatively be formed of a suitable plastics material.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)

Abstract

Un régleur automatique de longueur mécanique, utilisé par exemple comme régleur automatique de jeu dans un mécanisme de train de soupapes, comporte un logement (10) à filetage intérieur, une vis solide (14) ainsi qu'un ressort (20) de compression de bobine, agissant pour solliciter la vis vers l'extérieur du logement sur les flancs de guidage coopérants des filetages. L'autre extrémité du ressort (20) s'appuie sur un guide (22) en contact de support de faible frottement sur une fermeture (30) d'extrémité en acier à ressorts ajustée dans l'extrémité de l'alésage du logement.
PCT/GB1990/000293 1989-03-10 1990-02-26 Regleur automatique de longueur Ceased WO1990010786A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB898905592A GB8905592D0 (en) 1989-03-10 1989-03-10 Automatic length adjuster
GB8905592.5 1989-03-10

Publications (1)

Publication Number Publication Date
WO1990010786A1 true WO1990010786A1 (fr) 1990-09-20

Family

ID=10653139

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1990/000293 Ceased WO1990010786A1 (fr) 1989-03-10 1990-02-26 Regleur automatique de longueur

Country Status (2)

Country Link
GB (1) GB8905592D0 (fr)
WO (1) WO1990010786A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001057367A2 (fr) 2000-02-02 2001-08-09 Mckechnie Specialist Products Limited Dispositif de reglage de jeu de soupape automatique
WO2019243159A1 (fr) 2018-06-18 2019-12-26 Bayer Aktiengesellschaft Conjugués liant-principe actif inhibant cxcr5 comprenant des éléments de liaison pouvant être fragmentés de manière enzymatique et présentant un profil d'action amélioré

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2033472A (en) * 1978-08-17 1980-05-21 Gkn Fasteners Ltd Automatically adjusting valve clearance
GB2160945A (en) * 1984-06-27 1986-01-02 Gkn Technology Ltd Automatic valve clearance adjuster
GB2211263A (en) * 1987-12-19 1989-06-28 Gkn Technology Ltd Mechanical automatic clearance adjuster

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2033472A (en) * 1978-08-17 1980-05-21 Gkn Fasteners Ltd Automatically adjusting valve clearance
GB2160945A (en) * 1984-06-27 1986-01-02 Gkn Technology Ltd Automatic valve clearance adjuster
GB2211263A (en) * 1987-12-19 1989-06-28 Gkn Technology Ltd Mechanical automatic clearance adjuster
WO1989005898A1 (fr) * 1987-12-19 1989-06-29 Gkn Technology Limited Systeme de reglage automatique de jeu

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001057367A2 (fr) 2000-02-02 2001-08-09 Mckechnie Specialist Products Limited Dispositif de reglage de jeu de soupape automatique
WO2019243159A1 (fr) 2018-06-18 2019-12-26 Bayer Aktiengesellschaft Conjugués liant-principe actif inhibant cxcr5 comprenant des éléments de liaison pouvant être fragmentés de manière enzymatique et présentant un profil d'action amélioré

Also Published As

Publication number Publication date
GB8905592D0 (en) 1989-04-19

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